95 LT1 vette DataMaster File help
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 27
Likes: 0
From: Morton IL
95 LT1 vette DataMaster File help
Hi - Looking for some advice. I have a 95 Corvette 383 - mild cam, Head ported, small compression increase (rest stock looking - no headers etc) - all work done about 2 years ago. Was a very strong running - like a jack rabbit when hitting the throttle. Now very poor throttle response (from a stop) - adding throttle at cruise speed seems to create engine knock (computer pulling spark - Although knock counts don't seem to increase)
At the end of the log-file after pulling into the garage notice how the computer is pulling spark when I shift into gear (automatic) - goes to 12 degree of retard (engine idle also slows down) - shifting into neutral increases idle speed and immediately adds spark advance.
Here are my questions
Do I have a mechanical issue? (This seemed to happen all at once)
Do I have a tuning issue? (have not changed the tune since the build about 2 years ago)
Here is the file - https://rapidshare.com/files/9616444...tNoChanges.uni
Thanks I appreciate any help - email me with any ?
farney56 at gmail dot com
At the end of the log-file after pulling into the garage notice how the computer is pulling spark when I shift into gear (automatic) - goes to 12 degree of retard (engine idle also slows down) - shifting into neutral increases idle speed and immediately adds spark advance.
Here are my questions
Do I have a mechanical issue? (This seemed to happen all at once)
Do I have a tuning issue? (have not changed the tune since the build about 2 years ago)
Here is the file - https://rapidshare.com/files/9616444...tNoChanges.uni
Thanks I appreciate any help - email me with any ?
farney56 at gmail dot com
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 27
Likes: 0
From: Morton IL
Thanks - I suspected something like that - didn't know that it had a default mode though. I think that it has an LT4 knock module in the computer so I will change back to the original module and see what happens. After that plan on putting new knock sensors on - sound like a plan?
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 27
Likes: 0
From: Morton IL
I have made some progress. I replaced the LT4 knock module with my original LT1 module and thought that it solved the problem. Although I finally was able to get it to reproduce the shift into gear and spark retard goes to -12 degrees problem. Take it back out on the road and blow the cobs out of it and it would run good again. Finally noticed that the check engine light would come on (when setting still in the drive) and the -12 retard would start immediately. Then got to checking DTC codes and code 43 was set - Has to do with knock sensor circuit. Reset the computer by disconnecting the battery and that cleared the 43 code. Drove to the Chevy dealer that said he had one sensor (turned out it was for a 2005 not a 1995) and back (about 30 miles). So far the DTC code has not reset and car runs decent. So at this point I think that I'm going to drive it with the laptop hooked up and see what happens.
So STL94LT1 you definitely called it - the car was going into default mode - just not quite sure what caused it yet.
Thanks Again
So STL94LT1 you definitely called it - the car was going into default mode - just not quite sure what caused it yet.
Thanks Again
Racer
Joined: Jan 2004
Posts: 458
Likes: 1
From: NY
I have made some progress. I replaced the LT4 knock module with my original LT1 module and thought that it solved the problem. Although I finally was able to get it to reproduce the shift into gear and spark retard goes to -12 degrees problem. Take it back out on the road and blow the cobs out of it and it would run good again. Finally noticed that the check engine light would come on (when setting still in the drive) and the -12 retard would start immediately. Then got to checking DTC codes and code 43 was set - Has to do with knock sensor circuit. Reset the computer by disconnecting the battery and that cleared the 43 code. Drove to the Chevy dealer that said he had one sensor (turned out it was for a 2005 not a 1995) and back (about 30 miles). So far the DTC code has not reset and car runs decent. So at this point I think that I'm going to drive it with the laptop hooked up and see what happens.
So STL94LT1 you definitely called it - the car was going into default mode - just not quite sure what caused it yet.
Thanks Again
So STL94LT1 you definitely called it - the car was going into default mode - just not quite sure what caused it yet.
Thanks Again
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